1. Field of the Invention
The present invention relates to centerless grinders. More particularly the present invention relates to grinders wherein the stock is continuously unwrapped from a first spool and wrapped on a second spool during the process of grinding.
2. Description of the Related Art
Centerless grinders are well known machines for grinding elongated cylindrical workpieces such as medical guide wires, rods, pins, golf club shafts, antenna, fishing rods and similar articles. Conventional centerless grinders include a supporting structure on which a grinding wheel and a regulating wheel are mounted with their working surfaces facing each other and slightly separated. The workpiece is positioned between these two wheels (“the working area”). These wheels rotate in the same direction about a substantially horizontal axis at different speeds. The profile of the finished workpiece is controlled by moving the regulating wheel toward or away from the grinding wheel as the workpiece passes through the working area.
Since the workpiece's forward movement between the grinding wheel and the regulating wheel is controlled by the regulating wheel's speed and tilt angle (among other factors), slight changes in either of these factors can result in errors in the workpiece's desired grinding profile. In order to prevent such errors, systems employing optical sensors, such as those disclosed in U.S. Pat. No. 5,480,342 to Royal Master Grinders, Inc., the assignee of the present application, are used to precisely detect the workpiece's position and to move the regulating wheel in response to this detected position.
However, for elongated workpieces fabricated from wire stock shipped on spools, the grinding process can begin for a particular set of workpieces only after the wire is dispensed by hand from the spool and cut into a plurality of equal lengths. Each length of wire then must be placed into a feeder for transmitting the wire through the working area. These steps substantially delay the manufacturing process. Therefore, there is a need for a grinding machine that would continuously feed the wire past the grinding wheel and simultaneously continuously wrap the ground wire on a spool.